CCR is important because it eliminates the requirement for a shared storage subsystem for your Exchange cluster. Using CCR you can build a geographically distributed cluster, provided you have enough bandwidth between the nodes.

CCR operates using an Exchange cluster with a minimum of three nodes. Two nodes in an active/passive configuration contain the matching mailbox servers. The third node — the votersplit brain syndrome. — is used to avoid an occurrence of network partition within the cluster, also known as

When enabled, the CCR volume is seeded automatically with an ESE Full backup and is updated continuously with new transaction log files. Once copied to the CCR volume, the log files are applied immediately to the replicated database. To help make this practical, transaction log files are now 1MB in size vs. 5MB for Exchange 2003.

CCR will be important for organizations that desire more disaster recovery flexibility for Exchange.

One Comment

Wow- thats amazing! Exchange will finally get a application-layer cluster technology – that will hopefully work by its first or second service pack – allowing true multi-site DR. At last!

Is that 10 or more years behind Domino ? I forget. Domino v4.5 had this feature – around the timeframe that Exchange v4.5 beta was first published.

I was truly shocked at a meeting between a Microsoft published author and consultant, and a CIO of a large financial firm, bemoaning the fact that they couldnt actually do “true” DR for Exchange, even in Exchange 2003.

As a Domino guy, the thought of NOT having either close-time replica of all my environment, or indeed clustering of critical servers across sites/countries/continents sends a shiver across my spine.

Consider the case. On september 11th, 2001, I was working in a city of London bank, and was able to successfully initate, complete and rewire the companies eMail and non-structured databases and replication in the two hours or so before the Manhattan office power was shut down – AFTER the office was evacuated.

Can Sharepoint/Exchange do that NOW – five years on ? I think not. Time I think for large MS customers to re-evaluate what they’re getting for their licensing dollars…